/Engine/Source/Runtime/GeometryCore/Public/DynamicMesh/DynamicMesh3.h
Mesh Edit operations Compact mesh in-place, by moving vertices around and rewriting indices. Should be faster if the amount of compacting is not too significant, and is useful in some places.
void CompactInPlace ( [FCompactMaps](API\Runtime\GeometryCore\Util\FCompactMaps) * CompactInfo )